Function TestRing_ShuffleShard_Caching

ring/ring_test.go:4075–4207

This test checks if shuffle-sharded ring can be reused, and whether it receives updates from "main" ring.

(t *testing.T)

// This test checks if shuffle-sharded ring can be reused, and whether it receives
// updates from "main" ring.
func TestRing_ShuffleShard_Caching(t *testing.T) {
	t.Parallel()

	inmem, closer := consul.NewInMemoryClientWithConfig(GetCodec(), consul.Config{
		MaxCasRetries: 20,
		CasRetryDelay: 500 * time.Millisecond,
	}, log.NewNopLogger(), nil)
	t.Cleanup(func() { assert.NoError(t, closer.Close()) })

	cfg := Config{
		KVStore:              kv.Config{Mock: inmem},
		HeartbeatTimeout:     1 * time.Minute,
		ReplicationFactor:    3,
		ZoneAwarenessEnabled: true,
	}

	ring, err := New(cfg, "test", "test", log.NewNopLogger(), nil)
	require.NoError(t, err)
	require.NoError(t, services.StartAndAwaitRunning(context.Background(), ring))
	t.Cleanup(func() {
		_ = services.StopAndAwaitTerminated(context.Background(), ring)
	})

	// We will stop <number of zones> instances later, to see that subring is recomputed.
	const zones = 3
	const numLifecyclers = zones * 3 // 3 instances in each zone.

	lcs := []*Lifecycler(nil)
	for i := 0; i < numLifecyclers; i++ {
		lc := startLifecycler(t, cfg, 500*time.Millisecond, i, zones)
		lcs = append(lcs, lc)
	}

	// Wait until all instances in the ring are ACTIVE.
	test.Poll(t, 5*time.Second, numLifecyclers, func() interface{} {
		active := 0
		rs, _ := ring.GetReplicationSetForOperation(Read)
		for _, ing := range rs.Instances {
			if ing.State == ACTIVE {
				active++
			}
		}
		return active
	})

	// Use shardSize = zones, to get one instance from each zone.
	const shardSize = zones
	const user = "user"

	// This subring should be cached, and reused.
	subring := ring.ShuffleShard(user, shardSize)

	// Do 100 iterations over two seconds. Make sure we get the same subring.
	const iters = 100
	sleep := (2 * time.Second) / iters
	for i := 0; i < iters; i++ {
		newSubring := ring.ShuffleShard(user, shardSize)
		require.Same(t, subring, newSubring, "cached subring reused")